When Mario and his Partners came to his room (Cabin 4) he was hidden. Mario had to hide with Vivian for a couple of seconds to make him appear. When he did, he asked Mario to find his diary. Ghost T. warned Mario not to read it.

When Mario finds the diary, he has an option to read it - if he reads it he will get a Game Over (He will have the option to save and read it before returning it).

If Mario agrees to read the Ragged Diary, he will read the following:

Month X Day X Cloudy

I got on a train today,

And on that train...

After Mario read this, Ghost T. appears, and yells at Mario and co. for not listening to him, followed by giving him an automatic Game Over.